A queen odour mediates reproductive suppression in a eusocial mammal

Eusociality is a hallmark of social evolution but is exceptionally rare in mammals. Naked mole-rats exemplify this system, with reproduction confined to a single queen while subordinates remain infertile. We identify a queen-derived olfactory signal that elevates prolactin, suppresses subordinate reproduction, and maintains social stability. Withdrawal of the signal rapidly triggers aggression and reproductive competition, underscoring its causal role in colony cohesion. This provides the first evidence that a single chemical cue can enforce reproductive suppression in a mammal, revealing a conserved strategy linking insect and mammalian eusociality.